1. Field of the Invention
The invention relates to extraction cleaning machines. In one of its aspects, the invention relates to an upright deep cleaner machine that is adapted to deliver a cleaning solution at an elevated temperature suitable for effective cleaning. In another of its aspects, the invention relates to a hand-held portable extraction cleaner which is adapted to deliver a cleaning solution at an elevated temperature suitable for effective cleaning. In yet another of its aspects, the invention relates to an extraction cleaner machine which is adapted to maintain a cleaning solution at an elevated temperature suitable for effective cleaning without any electrical heating elements.
2. Description of the Related Art
Extraction cleaning machines, or extractors, include a solution dispensing system for applying a cleaning solution to a surface being cleaned and a fluid recovery system for drawing the applied solution from the surface by application of a suction airflow.
It has been found that a cleaning solution used in an extractor is more effective when applied at an elevated temperature. In prior art extraction cleaning machines, the cleaning solution has been elevated to the proper temperature by one of two methods: the solution tank has been filled with heated fluid from an external source, or the solution has been heated during dispensing such as by an in-line heater.
The use of pre-heated solution has the disadvantage that as the user proceeds with using the extractor the solution tends to cool to a sub-optimal temperature, decreasing the effectiveness of the solution. The use of an in-line heater has the disadvantages of adding cost to the extractor. Further, during high flow rate periods of operation, the in-line heater can have trouble maintaining the dispensed solution at the proper temperature due to the temperature differential between the solution in the solution tank and the desired dispensed solution temperature.
It would be advantageous to provide an extraction cleaner a means to reduce heat loss in a pre-heated fluid to either eliminate the need for an in-line heater or increase the efficiency of the in-line heater by reducing the temperature differential between the solution in the solution tank and the optimal dispensing temperature of the cleaning solution.
According to the invention, a portable surface cleaning apparatus of the type that includes a base module for movement along a surface to be cleaned and an upright handle pivotally mounted to the base module, a fluid recovery system for recovering soiled fluid from the surface to be cleaned and a liquid dispensing system for applying liquid to a surface to be cleaned includes a thermally insulated fluid supply tank. The insulated fluid supply tank can be formed with an inner wall and an outer wall.
In one embodiment, the inner wall and the outer wall are separated by an air space therebetween. In this embodiment, integrally molded ribs are preferably formed between the inner wall and the outer wall for maintaining a separation distance between the inner wall and the outer wall.
In another embodiment, the inner wall and the outer wall are separated by an insulating material. The insulating material can be foam or a fibrous batting.
In another embodiment, the inner wall, and preferably, the outer wall is a flexible bladder. In another embodiment, the insulated fluid supply tank wall comprises a foam material. For example, the fluid supply tank can be formed of closed-cell foam that forms one or both of the inner and outer surfaces of the fluid supply tank.
In yet another embodiment, the thermally insulated tank wall includes an insulation coating. The insulated coating can be applied directly to an outer surface of a single layer tank.
Further according to the invention, a hand-held surface cleaning apparatus that includes a fluid recovery system for recovering soiled fluid from the surface to be cleaned and a liquid dispensing system for applying liquid to a surface to be cleaned includes a thermally insulated fluid supply tank. The insulated fluid supply tank can be formed with an inner wall and an outer wall.
In one embodiment, the inner wall and the outer wall are separated by an air space therebetween. In this embodiment, integrally molded ribs are preferably formed between the inner wall and the outer wall for maintaining a separation distance between the inner wall and the outer wall.
In another embodiment, the inner wall and the outer wall are separated by an insulating material. The insulating material can be foam or a fibrous batting.
In another embodiment, the insulated fluid supply tank wall comprises a foam material. For example, the fluid supply tank can be formed of closed-cell foam that forms one or both of the inner and outer surfaces of the fluid supply tank.
In yet another embodiment, the thermally insulated tank wall includes an insulation coating. The insulated coating can be applied directly to an outer surface of a single layer tank.